This is a handy way to select and download individual files to import into your client.
For example, if you already have part of the blockchain and want to snag some of the newer files, you can do so instead of having to sync from other nodes.
If you haven't yet synchronized your client, you will want to use the bootstrap.dat file instead.
For quicker results, set maxconnections=0 while importing.
After import, close client, then set to maxconnections=2 while syncing
After syncing, close client, then set maxconnections=12 and restart.
When Fastcoin imports the blockchain and builds the index, connecting clients will try to send block data which reduces the client performance while building the database.
Even while synchronizing the blockchain, if you are connected to many clients at once, it will actually reduce the performance of incoming data. Once the blockchain is fully up to date, you can restart the client using any number of connections as it will no longer hinder the synchronization performance.
Be sure to run your client with -reindex -dbcache=1024 after placing the blk*.dat files in your /blocks/ folder.